From what I've noticed in my limited experience with these systems, the Sega AC adapters run a bit hot, specifically due to the voltage and milliamp rating (my last one was 10v 850ma). I torched one of my PC Engine Duo's by running this AC adapter on an unshielded power strip, and after the first surge, the system went *pop*, and I had to do a few surgical fixes to get it back online. I went to a electronics store and got a 9v 1000ma supply with a positive plug, the parts to adapt it to the duo with the supply included was $16.47. I got a plug adapter with it too. Waaaaay cheaper than spending $70 - $120 for an original one.